Molting party

lampeye · Post by **lampeye** » Tue Oct 31, 2006 7:04 am

Do crays in groups synchronize their molts? I ask because in the last 24 hours, four of my cajuns molted. I'm used to finding a few sheds in the tank a week, but one went early yesterday morning and three last night following a water change. I had the pleasure of witnessing it occur for my largest female. She was eating, then rolled on her side, and did her thing.

Considering the unusual reproductive biology, it would make sense for them to do so - if a female goes into mating mode, it would make sense for males to go into breeding mode asap, and for other females, too.

The water change may have triggered it as well - thoughts?

YuccaPatrol · Post by **YuccaPatrol** » Tue Oct 31, 2006 8:42 am

The water change likely contributed to the the molting.

I did a water change a few days ago and suddenly had a bunch of female crays carrying eggs.

Post by **Mustafa** » Tue Oct 31, 2006 9:35 am

Yes, that would make sense. However, there might be a simpler explanation. Since they are all fed about the same amount of food in an aquarium, they might just grow at about the same rate and shed at about the same rate. In nature the rate of food intake of any given crayfish is likely to be different from the others.

lampeye · Post by **lampeye** » Tue Oct 31, 2006 9:39 am

That is even simpler, but the four that molted in the 24 period in question were of varying sizes. I doubt the growth rates are that close.

It could also have been an utter coincidence.

I was just a little surprised to see so many sheds in the tank this morning and it got me thinking.

From an evolutionary standpoint, it would (could, I should say) be of great benefit for a male to be able to "rush" his molt a bit to get into reproductive mode if he smells breedable females. IF that is possible, it would be of great benefit for females to be able to do so as well, especially in Cambarellus, as they seem to be adapted to temporary bodies of water. The cost of not putting on maximum growth could be offset by making breeding a "now" instead of "later" proposition.

Smells like an undergrad research project to me.

lampeye · Post by **lampeye** » Tue Oct 31, 2006 9:45 am

YuccaPatrol wrote:The water change likely contributed to the the molting.

But that's so boring!

YuccaPatrol · Post by **YuccaPatrol** » Tue Oct 31, 2006 9:46 am

lampeye wrote:
YuccaPatrol wrote:The water change likely contributed to the the molting.
But that's so boring!

Would a lunar phase hypothesis be more fun?

Neonshrimp · Post by **Neonshrimp** » Tue Oct 31, 2006 10:07 am

Would a lunar phase hypothesis be more fun?

Hey, doesn't it work for human females

Cableguy · Post by **Cableguy** » Tue Oct 31, 2006 10:57 am

could be alien growth hormones in the water!

badflash · Post by **badflash** » Tue Oct 31, 2006 11:26 am

Can't say for sure with crays, but I know a BAD water change will trigger molts in shrimp. I saw this recently with the survivors of my all too recent water change distaster. Those that lived all motled the same day. When you see 50 shrimp shells all over the place after pulling out a bunch of dead ones, your heart sort of stops. No more losses after I rescued them and re-treated the water.

Keep in mind that this is the time of year that the water company changes their water treatment from summer to winter. Lots of crap comes out of the pipes when the chemical concentrations change. I'm sure that is what happened to me this year, and last year at the same time, so beware. Prime was not up to this challenge with my water.

CanadianCray · Post by **CanadianCray** » Tue Oct 31, 2006 6:15 pm

Yes there have been studies of this. When kept in numbers together for long periods in enclosed systems like aquariums or closed aquaculture systems crayfish will synchronize their molts. Its usually males that synch to other males & females to females. I will find the article & post a link to it. Has to do with hormones the males & females release into the water.

Neonshrimp · Post by **Neonshrimp** » Tue Oct 31, 2006 6:37 pm

Keep in mind that this is the time of year that the water company changes their water treatment from summer to winter. Lots of crap comes out of the pipes when the chemical concentrations change. I'm sure that is what happened to me this year, and last year at the same time, so beware. Prime was not up to this challenge with my water.

Thanks again for this warning, this is something I will be sure to watch out for since I only started with shrimp last winter

FISH WORLD ERIE · Post by **FISH WORLD ERIE** » Tue Oct 31, 2006 7:32 pm

I have noticed this in my tanks as well. I am pretty sure it has to do with the phermones the crays naturally release. It kind of puts them all in sync. This happens with female humans as well. Not molting. But their monthly cycles will align if they live under the same roof for a long period of time. I am not an expert just a good observer and listener so do not take my words as gold. Lunar cycles also sound good

badflash · Post by **badflash** » Tue Oct 31, 2006 7:48 pm

The alpha female (human) in the household will sync up the rest of them. I've seen it many times so it is fact not folklore. I'm sure the same goes for crays.

I keep M. rosenbergii and they also do odd stuff with hormones. The alpha male puts out something that supresses the growth and form of the other males for quite a while. In my pool of shrimp that all went post larval from the same hatch I have just 1 9" male blue claw one or two small 4" blue claws that are hiding and missing arms, lots of orange claws (sub dominant males), a bunch of small males only 2" or less. The females are a pretty uniform 4". If I was to remove the alpha male, the other blue claws would duke it out and one would win, get huge and replace the current alpha male. Eventually an orange claw will be bigger, molt to blue claw and kill the alpha if the alpha if he can't kill him while he's soft. nasty buisness.

lampeye · Post by **lampeye** » Fri Nov 03, 2006 6:07 am

Life is a nasty business.

BTW, the males of some fish seem to be able to supress growth in other males, as well.

Cableguy · Post by **Cableguy** » Fri Nov 03, 2006 7:42 am

lampeye wrote:Life is a nasty business.

BTW, the males of some fish seem to be able to supress growth in other males, as well.

i noticed this with my corydorus fry, lots of water changes seem to lesson the concentration of hormones/pheramones though